Phillb k



R K.DEVEBS Jm INCLOSED ARC DEVICE.

APPLICATION FILED MAR-6.1916.

1,310,067. Patented July 15, 1919.

Inventcw: Fhi H K. Davers 'Jn, by 1 UNITED STATES PATENT orrion.

PHILIP K. DEVERS, JR, 015 LYNN, MASSACHUSETTS, ASSIG-NOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INCLOSED ARC DEVICE.

Specification of Letters Patent.

Patented July is, 1919.

Application filed March 6, 1916. Serial No. 82,378.

at Lynn; in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Inclosed-Arc Devices, of which the following is a specification.

The present invention relates to electric are devices, particularly inclosed arc lamps, in which an arc is operated between electrodes of refractory material in a gas or vapor at high enough pressure to largely suppress disintegration of the electrodes. It is the object of my invention to provide improved means for facilitatingthe starting of the arc.

In a co-pending application, Serial No. 82,377, filed on even date herewith, I have described and claimed an arc device containing a gaseous filling and provided with a heater adjacent the the arc.

My present invention comprises an inclosed arc device containing a quantity of easily vaporizable material, for example,

mercury, or an amalgam, and a heater lo 'cated to vaporize said material and to thermally ionize the vapor and produce ionization of the electrodes when subjected to a difference of potential by the impact of the ionized vapor upon the electrodes.

In one of its aspects my invention co1nprises an inclosed arc device provided with means for furnishing the vapor of an alkali metal, for example, potassium, to the arcing space between electrodes of refractory material, as, for example, tungsten, to facilitate the starting of an are between said electrodes. These and other aspects of myinvention will be more fully describedin the following description taken in..-co'nnection with the accompanying di- -awing and the novel features of my ..in'vention will be specifically pointedout in the appended claims.

The drawing shows in Figure 1 an inclosed incandescent arc lamp provided with my improved starting means and connected toa mechanism for automatically discon nectlng the starting devlce when the arc 1s operating; Fig. 2 shows diagrammatically a modification in which current for the heater is furnished by a separatesource; and Fig. 3 illustrates another modlficatlon electrodes for startingv in which the are and the heater are supplied by the same source.

Referring to Fig. 1 of the drawing, the arc device, in this instance, a lamp, comprlses a container 1 containing electrodes 2, 3 of tungsten, or other suitable refractory 'material. The electrodes are carried by thin supports 4,5, preferably consisting of tungsten. They are connected to leading-in conductors 6, 7 sealed into the container in the usual manner. The globe or container lcontains a gas inert, or substantially so, with respect to the electrodes at the operating temperature, for example, argon, neon, krypton or nitrogen. The gas should be at a pressure high enough to suppress disintegration, or sputtering, of the electrodes at starting, say, a pressure at least above several millimeters of mercury, a pressure of about 25+ millimeters being preferred. In a lamp the gas should have a relatively poor heat conductivity to enable the electrodes to be heated as highly as possible to give a maximum lighting efficiency, hydrogen for that reason being distinctly unsuitable. Some of the advantages of my invention may be secured in a device containing no fixed gas. The bulb also contains a quantity of easily vaporizable material 8, for example, mercury, or low melting alloy, which when vaporized will supply an atmosphere of vapor in which a high efiicienc'y are may be operated between the electrodes 2, 3. As will be later explained an amalgam of an alkali metal is in some cases to be preferred to mercury; The envelop has a constriction at 9 giving the effect of tWo chambers. The evolution of vapor from the mercury or the like displaces the argon or other gas into the upper chamber. The effect of the constriction is to substantially increase the efficiency of the lamp;

An incandescible conductor or heater 10 is located below the electrodes between which the arc is intended to be operated and dips into the vaporizalble material. This heater alsopreferably consists of tungsten and is proportioned to be raised to a temperature of about 2-000 C. under the operating conditions hereinafter described. For example, the heater may consist of 0.015 tungsten wire, and may be arranged about below the electrodes. The spur or loop 11 projects into the mercury as shown by a -velop. conductors 12, 12,

. eluded infa series circuit 16, which may con- 2, 3, the full potential of tain other are devices of the character described herein. The heater 10 -is connectedto one terminal of the supply source through the conductor .17", amagnet winding 18, a conductor 19, a cut-out contact 20, and the conductor 21. The heater is connected to the opposite terminal of the compensator by the conductor-s6 and 13. 1

When the switch 22 in the circuit 13 is closed the heater 1 0,with. a. current, say, of 12 amperes, becomes incandescent, vaporizing and ionizing some of the mercury or other easily vaporizable material. 'As the disengaged vapor comes into contact with the. heater wire it becomes still further ionized and impinges on the surface of the electrodes which are themselves heated and ionized to some .extent.

The current, in the coil 18 causes the core 23' connected to the lifted, the dash-pot being adjusted, for a predetermined time interval long enough permit.the ionization to proceed to a point where an arc may be started, for example, four or five seconds. l/Vhen the stop 25 comes into engagement with the lever 26 the cut-out 20 is tripped, opening the heater the arcelectrodes the coil 15 in the series circuit which, for example, may be circuit and impressing on 200 volts. As the electrodeshave already,

been subjected to ionization influence, an arc is started immediately, and the are current comes to an equilibrium 1n a few seconds at a lower voltage, for example, 15

volts in' a 12 ampere circuit. The coil 27 in the arc circuit 11, 21 now being traversed by current causes its core 28 to be attracted thus maintaining the heater circuit open,

even when the core 23 has returned to its starting position.

hen an alkali metal as, for example, potassium, sodium, rubidium 'or the like is added to the mercury in an amount sufficient to form a rich amalgam, an arc can be started between the electrodes at a lower voltage and with a lower wattage consumed in the heater. For example, in a lamp such as described above, a heater current of but 8 anipcres is suflicient to start an arc in about 5 seconds, at an impressed potential as low as 75 volts.- W'lien using an alkali metal the inclosing envelop should consist dash-pot 24 to be slowly of suitablealkali resisting glass which may be purchased in the market.

In Fig. 2 the electrodes 2, 3 are connected to the secondary of a transformer 29 by theconductors 30, 31, and the ionizer 10 is connected to one terminal of the secondary of by, a conductor 35. lVhen the switches 22 and' 36 are closed, the heater is traversed by current, as above described in connection with Fig. 1, and the armature of the magnet 18 is pulled up. Assuming the transformers 29 and 32 to be in parallel, it is neces- I sary to break the heater-circuit before the full potential of the transformer'29 is impressed upon the electrodes. Therefore, when the cut-out 20 opens the arcwillstart as described in connection-with'Fig; 1.- The arc current will cause the armature of the magnet 27 to maintain the cut-out contact open.

When the heater circuit is not in parallel with the arc and does not affect the electrical characteristics of the arc circuit, but issupplied with current from an independent source of energy, than the magnet 18, to-

gether with the lever 26, may be omitted,

and the magnet 27 will open the heater circiiit as soon as the arcstarts.

If desired the heater orzionizer may be connected to the terminals of the arc supply source'as shown in Fig. 3. The conductors supplying the heater are connected in series with a double break cut-out 37. When the magnet 18 which is'in series with the heater has pulled up its armature far enough to open the cut-out 37, the full. open-circuit transformer "potential is, impressed across electrodes 2, 3 thereby starting the are.

What I claim as new and desire to secure w- Iiby Letters Patent of the United States, is: I

1. An electric arc device comprising the combination of a sealed container, electrodes of refractory material therein, a quantity of an amalgam of an alkali metal and means distinct from said electrodes for vaporizing and ionizing part of sa d amalgam preliminary to starting an arcbetween said. electrodes. v

2. An electric arc device comprising the combination of a sealedjcontainer, electrodes of tungsten therein, a quantity of potassiumamalgam, a resistance means for vaporizing part of said amalgam and means for impressmg a current upon said electrodes having a: potential high enough to start an are between said'electrodes.

3. An electric arc device comprising the combination of a sealed envelop, electrodes of refractory conducting material therein, a quantity of easily vaporizable material, electrically heated means for vaporizing and I vaporize at least some of said metal and to ionizing said material, and means for impressing upon said electrodes, a current having a potential substantially higher-than necessary to maintain an are between said electrodes while simultaneously deenergizing the vaporizing and ionizing means used for starting.

4:. An electric arc device comprising the combination of a sealed container, electrodes of tungsten therein, a quantity of liquid metal, an electric heater in contact with said metal and located in part between the liquid metal and said electrodes, and current connections independent of said metal for heating said resistance preliminary tostarting an are between the tungsten electrodes.

5. An electric arc device comprising the combination of a sealed envelop, electrodes of refractory material therein, a quantity of easily vaporizable metal, a heater located to ionize the vapor to facilitate the starting of an are between said electrodes at a moderate potential, and means for starting an are be tween said electrodes subsequent to the vaporization of said metal.

6. An electric arc device comprising the combination of a sealed envelop, electrodes of refractory metal therein, a quantity of liquid easily vaporizable metal, and a filament. adapted to be independently heated located in part above the surface of said vaporizable metal, and in part dipping into said metal.

7. An electric arc device comprising the combination of a sealed envelop, tungsten electrodes therein separated by a gap, a quantity of mercury and an independently incandescible conductor located in-part be tween the mercury and said electrodes and in contact with said mercury.

S. An electric arc device comprising the combination of a sealed envelop, tungsten electrodes therein separated by a gap, a quantity of mercury alloyed with an alkali metal, and an independently incandesc'ible conductor located in part between the mercnry and said electrodes in contact with said alloy.

9. An electric arc device comprising the combination of a sealed envelop, tungsten electrodes therein separated by a gap, a quantity of potassium amalgam, and an independently incandescible conductor located in part between'th'e amalgam and said electrodes and in contact with said potassium amalgam.

10. An electric arc dev tion to said mercury and said electrodes, and electrical connections therefor at least one- ,of which 15 independent and said electrodes.

12. An electric arc lamp comprising the combination of a sealed coi'itainer, electrodes of tungsten located in said container, leading-in wires therefor sealed into said container, a filling of gas inert with respect to incandescent tungsten and having a pressure high enough to materially suppress electrical disintegration of said electrodes when an arc is operating between the same, a quantity of amalgam of an alkali metal in said container located in operative position of the lamp adjacent to but out of contact with said elec:

trodes, and a refractory heater located adja cent said electrodes and dipping into said amalgam, and means for incandescing said heater independently of the passage of current between said electrodes.

13. An arc device comprising the combination of a sealed envelop, electrodes of refrac tory material therein, a quantity of easily vaporizable material, electrothennal means for vaporizing and ionizing said material, an electroresponsive device for energizing said means, switching means for denergizing said electrothermal means and impressing a potential upon said electrodes, and means for timing said switching means to operate a predetermined interval after said electro-thermal device has been energized,

In Witness whereof, I have hereunto my hand this 3rd day of -Jlarch, 12316.,

Pllill'trll" hi. DEVEBS,JR.

of said mercury 

